Question

the perimeter of a semicircle metallic plate is it is 86.4 calculate the radius and area of plate​

Answer 1

Answer:

443.52cm2

Step-by-step explanation:

Perimeter of a semi circular plate =πr+2r

Given, πr+2r=86.4

      =>r(π+2)=86.4

      =>r=π+286.4

      =>r=722+286.4

      =>r=73686.4

      =>r=3686.4×7

      =>r=16.8 cm

Area of a semi circle =2πr2

                                    =7×222×16.82

                                    =443.52cm2

Answer 2

Answer:

radius (r) = 16.8 cm, area of plate = 443.52 cm^2

Step-by-step explanation:

Perimeter of a semi circular plate =πr+2r

Given,

πr+2r=86.4

r(π+2)=86.4

$r = \frac{86.4}{\pi + 2} \\ r = \frac{86.4}{ \frac{22}{7} + 2 } \\ r = \frac{86.4}{ \frac{36}{7} } \\ r = \frac{86.4 \times 7}{36} \\ r = 16.8 \: cm$

$Area of a semi circle = \frac{\pi {r}^{2} }{2} \\ = \frac{22 \times {16.8}^{2} }{7 \times 2} \\ = 443.52 \: c {m}^{2}$

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